Smooth out a concave edge
This is generally a result of the complexity of working with the subdivision surface modifier. The closer together your edge loops are, the more of a &quot;crease&quot; you will get.
To solve this, I would recommend individually selecting the edge loops on each side of the center edge loop where the crease is and edge sliding (double tap G) them away from each other until the &quot;crease&quot; is smoothed out. As an aside, you should consider if those three edge loops are even needed: is it possible to get away with only one?
Please edit your post to share your blend file too - it would really help!
You can use this site to share blend files: https://blend-exchange.giantcowfilms.com/